It has heretofore been the practice in vehicle leveling systems that function to maintain a predetermined height relationship between the chassis (sprung portion) of a vehicle and its ground engaging axle assemblies (unsprung vehicle portion), to utilize one or more auxiliary fluid suspension component(s) to supplement the load carrying capacity of the primary vehicle springs. A pressure source has been included in such leveling systems for supplying pressurized fluid to the auixiliary suspension components when a load of predetermined magnitude has been added to the vehicle chassis, whereby the auxiliary suspension components become operable to supplement the load carrying capacity of the primary springs to return the vehicle chassis to a level or other desired height relationship with respect to the ground engaging axle. When the vehicle load is removed, the primary suspension springs and pressurized auxiliary suspension components coact to cause the chassis to rise above the desired height relationship, thereby requiring that the pressurized fluid be exhausted from the auxiliary suspension components.
To accomplish the aforesaid pressurizing and exhausting of fluid from the auxiliary suspension components, it has been the practice to utilize some type of a height detecting controller located remote from the components at a suitable position between the ground engaging axle and vehicle chassis to sense sustained changes in the height relationship therebetween and control fluid flow between intake and exhaust valve components. Such remotely located controllers have been found to be objectionable for a number of reasons, including the fact that they necessitate separate factory or field installation, as well as require the use of a myriad of fluid couplings and linkages for operatively connecting the controller between the sprung and unsprung masses of the vehicle. Additionally, such remotely located height controllers have been subject to objectionable criticism due to the fact that they must be accurately positioned and adjusted apart from other components of the system in order to assure the desired overall operation of the system.
It has heretofore been proposed to integrate or combine such height controlling devices with the auxiliary suspension components, such as is disclosed in U.S. Pat. Nos. 3,584,894 and 3,606,475, through the utilization of mechanical switching devices located directly upon the auxiliary suspension components, thereby eliminating the need for mechanical linkages between the height controller and the vehicle's sprung and unsprung positions. Unfortunately, however, such mechanical switching devices have been found to be subject to wear and relate attrition due to the hostile operative environment thereof as well as the large number of interrelated moving mechanical components embodied therein.
The present invention provides a new and improved vehicle leveling system which is intended to overcome the various objectionable characteristics of combination auxiliary suspension components and height controlling devices in the prior art through the provision of a novel height sensing and controlling mechanism which is entirely without or void of any moving mechanical components which might be subject to objectionable wear, misadjustment, failure, etc. More particularly, the height sensing and controlling mechanism embodied in the present invention is designed to utilize either an optical or proximity type switching mechanism so that there is no mechanical interconnection between the sensing elements which are associated with the sprung and unsprung portions of the vehicle.
It is, therefore, a primary object of the present invention to provide a new and improved leveling system wherein the height sensing and controlling mechanism is combined directly with the auxiliary suspension components.
It is a more particular object of the present invention to provide a new and improved combined height sensing and controlling mechanism for an auxiliary suspension component which is entirely without mechanical interconnection between those parts thereof associated with the sprung and unsprung portions of the vehicle.
Still a more particular object of the present invention is to provide a new and improved height sensing control mechanism of the above described type which utilizes an optical system including a light source and means sensitive to said light source for controlling pressurization of the associated auxiliary suspension components.
It is a related object of the present invention to utilize a portion of the auxiliary suspension component as a shutter element for controlling the transmission of light between the light source and the light sensitive means.
It is a further object of the present invention to provide a new and improved leveling system of the above described type wherein the height sensing and controlling mechanism includes proximity switch means for providing an electrical signal responsive to the relative orientation of certain parts of the auxiliary suspension components associated with the sprung and unsprung portions of the vehicle.
It is still a further object of the present invention to provide a new and improved leveling system of the above described type which finds particularly useful application with an electrically energized air compressor.
It is yet another object of the present invention to provide a new and improved leveling system, as set forth above, which is of a relatively simple design, is economical to manufacture and will have a long and effective operational life.
Other objects and advantages of the present invention will become apparent from the following detailed description taken in conjunction with the accompanying drawings.